Process and means for recovering vanadium and uranium from ores



Oct. l5, 1940. H. D. BROWN y 2,217,665

PRCESS AND MEANS FOR RECOVERING VANADIUY AND URANIUM FROM @RES I FiledAug. 22, 193s van, m

. l* ATTORNEY.

`Patented Oct. 15, 1940 UN'ITTF-DEY STATES' -Pmjclrss AND MEANS Fon.`lalicovuiuncr VANADIUM ANDURANIUM FROM onus.V

Harry D. Brown, Palisade, 001g. v Application August 22, 1938, SerialNo. 226,086r 1 claim; f (c1. as is) AThis invention relates to a processand tothe means for carrying out the process for k.treating carnotiteand othervanadium-uranium lores for therecovery of .thefvanadium and/oruranium i values therefrom.- I .f i

The principal objectof `the inventionis to provide a continuous processby means of which the values maybe extracted ata minimum of cost.Another object of the inventionis to provide a highlyl ecient treatingmechanism which `will continuously and successivelyreduce or roast theore, then immediately oxidize the hot roast in the presence of heat andmoisture; thence collect the oxidized oreand `deliver it to a continuouscooling ll apparatus. l y

Other advantages result from the improved process and the apparatusemployed in carrying out the process. These will become more appar.; entfrom the following description. In the following detailed description ofthe invention reference is had to the accompanying drawing which formsapart-hereof. Like numerals refer to like parts in all views of thedrawing and throughout the description. Inthe drawing: Y

Fig. 1 is a longitudinal section through the improved treatmentapparatus which is employed in carrying out the improved process.

`vFig. 2 `is` a vertical cross section-therethrough taken on the line2-2, Fig. 1. f 1 l Fig. -3 is a detail section taken on the line 3'-3,Fig.1. 'f

The apparatus consists-of'a masonry furnace structure I2 lined with firebrick or` other -re resisting material. Are box or oxidizing cham#-v berI3, a precipitating chamber I`4,' and a con# vection chamber I5 arecontainedwithin the furnace structure.V The oxidizing chamber is sepavrated from the --precipitating chamber `I4kby im meansof ahollow backwall 311 inwhich there is a. relatively lo'w iire arch IIS. 'A-stack I'Icon- Veys the combustion gases from the far end ofy thecnvection chamberI5.

A rotating ore drum I0 extends completely throughout the length of theconvection chamber I5 and is supported on the exterior of the furnaceupon suitable bearing rollers II. The drum I0 is provided at oneextremity with a feed hopper I8, through a hollow trunnion I9, and atits other extremity carries an enclosed discharge chute 20. The drum isrotated from any desired source of power through the medium of asuitable drive sprocket 2| and is provided throughout its interior witha conveyor screw 22 and on its exterior communicating with the drum withinclined conveyor paddles l23, which extendY in a close .proximity totheWalls ofthe chamber A settlings passage-24 opensfrom the bottom of theconvection chamber I5 adjacent the pre- 5- cipitating chamber I4.- This.passage extends downwardly in the back wall 3l and separates to eachside of the arch Ivinto the side walls of the` furnace openingfto thelatter Abeneath the arch and `above a pair Vof screw-conveyors 25 10which extend-throughout the length ofthe bottom of the furnacestructure,-

The conveyors-25 are of the usual'h'ollow shaft type and arevwater-cooledby passing' water-from aL water supply 26`through the hollowconveyor 16 shaft 28. I rThe Iconveyors aredriven'from any suitablesource ofl powerthrough drive sprockets 29 and rotate in a direction toconvey material toaninclined ore passage 30 leadingto a revolvingcooling drum 3|. f I 20 A gas or oil burner 32 is positioned at oneextremity of the oxidizing chamber? I Beso as to blow a' iiame therein.This lburner lmay be lof any' suitable type to which fuelis furnishedthrough a fuel pipe 33 and air is furnished through -an 25 airpipe34. 'Yv,

Steam jets 35 are also' directed into the oxidizing chamber immediatelybelow the chute 2U.r A steam plate 36 is'positioned below the chute 20,and directly under the steam jets'35, toreceive 30 thel roasted materialfrom the roaster |015 f- Operation v 5.

Before being fed to the roastenthe ore is in# termixed with a suitablereagent' in predetermined 35 proportions. The particular` reagentemployed depends upon whethervthe'recovery-isto be'vanadium alone orboth vanadiumvand uranium. vThe choice, of course, depends upon theparticular ore being worked, as towhether there is sufficient ura. niumtherein to warrant extraction. If both vainadium and uranium are tofbeextracted, sodium chlorideI and/or: vsodium carbonate are-used. Shouldvanadium be the only product to be extracted, the sodium chloride alone.is preferred 45 as the reagent. y

The ore containing the proper percentage of the chosen reagent is fedinto the hopper I8 from whence it flows into the decrepitating drum orchloridizing roaster I0 through which it is slowly 50 conveyed by meansof the screw 22. 'Ihe heat in the convection chamber I5 and the speedoftravel of the ore are regulated to elect a substantially completedecrepitation or pulverization of the ore before it is delivered to thedischargev chute '55 20. The drum is sealed to provide a non-oxidizingatmosphere.

During its travel through the roaster, the ore is decrepitated by thedehydrating action of the heat and the impacts imparted by the cascadingrotating action so that preliminary grinding costs are greatly reduced.The ore discharges into the receiving chute 20 at a temperature ofapproximately rl50"`IE. From the chute, it falls upon the steam table 36into the steam blasts from the jets 35, which instantly blow the hot oreinto the oxidizing flame in highly dispersed condition intermixed withthe water particles in the steam. The name within theoxidizing chamberproduces a temperature of approximately 2000*" F. whichcompletelyoxdizes and calcines the ore and decomposes the steam tofurnish' additional oxidizing oxygen.

The combustion gases, with the suspended ore particles are deflecteddownward by the back 'wall 3,1 through the restricted opening below thearch I6. l,This throws a portion of the suspended oxidized ore or dustdownwardly onto the conveyors 25. The gases then enter theprecipitatingchamber I4 where they expand and lose velocity so as to,release the remaining suspended dust to the conveyors 25. The gases thenrise to and flow through the convection chamber l5 to the stack l1. Anyremaining ore dustrin the gases will be droppedin the convection chamberand will be conveyed back by means of Scrapers 23 to the settlingspassage 24 from whence it will fall downwardly around the arch I6 to theconveyors 25.

The, ore dust is collected and carried by the conveyors to the ore pass30 from whence it is de,- livered to the cooler 3l. The temperature ofthe calcined product flowing through, the ore pass 3l) is approximately1520 F.

,-After being cooled, the vanadium and uranium is dissolved from thecalcined ore in the basic leach. Y,

The reaction in the chamber Il is essentially a chloridizing roast. Theore decrepitates under this condition of heat in the non-oxidizingatmosphere of the drum thereby assisting reagent contact with themineral or minerals contained in the minute interstices of the sandgrains. Themineral or mineralsv having the power of combination arechloridized, intimately lmixed with the chloridizing reagent and `arerendered nascent for immediate oxidation. rI he speed of the chemicalreaction is greatly inuenced by temperature, by concentration of thereacting substances and by the intimacy and amount oi contact surfaceprovided in the chloridizing roast, by the cascading action and, in theoxidizing chamber, by the dispersion of the ore. The steam used to blowthe ore into the oxidizing chamber becomes dissociated and forms aneilicient oxidizing agent. 'I'he reaction in the oxidizing chamber isthat chlorine is liberated and passes off with the gases of combustion,while the sodium combines with the vanadium to form a water solublesodium vanadate.

In the event of using sodium carbonate with the i sodium chloride asreagents, a certain amount of carbonates are formed in the reducingchamber which persist throughout the roast. The CO2 combines with theuranium.

By decrepitating the ore during chloridization, the time required forvcalcining is greatly reduced, the reagent contact with the vanadium anduranium is more efficient, and the mechanical features of the roasterareA greatlysimplied, therefore both the initial cost and theoperatin'gcosts are low.

' The ore of the sodium chloride reagent roast is leaclled with water;The calcined ore renders the leaching solution basic. The soluble sodiumvanadate passes into solution and is then ready for precipitation. Thecombined reagents, sodium chloride and sodium carbonate, when used toArecover both uranium and vanadium from the ore vmust be treateddifferently in the leaching ,of same.` As above stated, a certainvamountof fthe CO2 combines with the uranium rbut insufficient to preventprecipitation that must be controlled. Therefore, just sufficient sodiumcarbonate is added to the leaching solution to keep the sodium uranylcarbonate in solution, the same being soluble in anexcess of `sodiumcarbonate. The vanadium is also soluble in this solution and the twoproducts may be selectively precipitated. By expelling the CO2 ofthesolution, uranium will precipitate as sodium uranate. Theprecipitationof the vanadium follows.

'Ihe machine is particularly valuable in providing an e'icient treatingmechanismof low initial cost and low operating cost. l

While this invention has been described as particularly applicable tocarnotite and other vanadium-uranium bearing ores for `the recovery ofvanadium and/or uranium values therefrom, it is not to be construed aslimited to these particular ores. Y,

While a specic-form of the improvement has been described andillustrated herein,it is desired to be understoodthat the same may bevaried, within the scope of the appended claim, Without departing fromthe spirit of the invention.

Having thus described the invention, what is claimed and desired securedbyLetters Patent is:

A process for treating vanadium ores to-form soluble vanadatescomprising: the steps of forming a mixture ofthe ore and a salt fromtheclass consisting of sodium chloride and sodium carbonate, subjectingthe mixture inaclosed drum to a heating and agitation in anon-oxidizingatmosphere, discharging the mixture `from the c' drum intoan oxidation chamber, dispersing the mixture therein by a steam `jetsubjecting the mixture while in a dispersed vcondition to -an ,oxidizingroast to convert the vanadium values 7thereingto vanadates, collecting vthe Yroasted product and leachingit to recover the vanadium values.

